1. Field of the Invention
The present invention relates to network management systems. Further, the present invention is directed to methods and systems that automatically discover nodes of a network, and in particular only the desired node types of the network.
2. Background Information
The ability manage networks efficiently is a necessity for institutions of all sizes. As technology continues to develop and be deployed to an increasing number of users and applications, networks become larger and more complex. Consequently, network management requires constant monitoring of the deployed nodes (i.e, computers, servers, routers, sub-networks, network enabled devices, and the like). The nodes may alternatively be referred to managed devices or node devices. Regardless of the term used, the node (or managed device or node device) refers to a piece of network equipment (including the equipment's software) that resides on a managed network. As part of the network monitoring process, the identity and quantity of deployed nodes should be identified.
The decentralization of computer networks has increased the complexity of tracking network topology. The network nodes may be linked in any one of a variety of schemes. Systems for determining and graphically displaying the topology of a computer network are known. U.S. Pat. No. 5,276,789 to Besaw et al. and U.S. Pat. No. 5,185,860 to Wu, both of which are assigned to the assignee of the present invention and are hereby incorporated by reference, describe such systems. As described in Besaw et al., the system retrieves a list of nodes and their interconnections from a database which can be manually built by a network administrator or automatically constructed using computer software. The system can be configured to provide any one of three views. An internet view shows nodes and interconnections of different networks. A network view shows the nodes and interconnections of a single network within the internet view. A segment view displays nodes connected within one segment of one of the networks. Selected nodes on the network, called discovery agents, can convey knowledge of the existence of other nodes. The network discovery system queries these discovery agents and obtains the information necessary to form a graphical display of the topology. The discovery agents can be periodically queried to determine if nodes have been added to the network. In a Transmission Controller Protocol/Internet Protocol (TCP/IP) network, the discovery agents are nodes that respond to queries for an address translation table which translates Internet Protocol (IP) addresses to physical addresses.
The Wu patent describes a system that operates on a TCP/IP network to using Simple Network Management Protocol (SNMP) to automatically discover nodes on the network. The Wu system makes use of the functionality of the SNMP protocol to query discovery agents on the network and thereby obtain a list of other nodes on the network known to the discovery agent. The system then uses this list to query other nodes in the list to find additional discovery agents among the list of other nodes. The process is repeated to automatically discover the nodes on the network. Additionally, the system repeats the process at timed intervals to identify nodes that were not available during previous the discovery process.
FIG. 1 shows a typical managed network 10 that can use SNMP to manage the and discover nodes on the network 10. A network management system 100 comprises a network manager 102 and a computer 104. The network management system is connected via interconnection 150 (e.g., copper wire, fiber optics, coaxial cable, wireless, and the like) to various nodes 110–130. Each node 110–130 contains an agent that communicates with the network manager 102. Although the actual data between the nodes 110–130 and the network manager 102 is transmitted over the interconnection 150, a protocol (e.g., SNMP) is necessary to communicate between the network manager 102 and the agents of nodes 110–130. The SNMP connections are shown as dashed lines between the agents and network manager 102. For example, the network manager 102 can query the agent in node 110 using SNMP. The agent then obtains the necessary data from node 110. Then, the agent of node 110 returns its response to the query to the network manager 102. Typically, the data is organized in a Management Information Base (MIB). Additional information regarding SNMP and MIB can be found in pages 535–551 of Ross and Kurose, “Computer Networking: a Top-down Approach Featuring the Internet”, Addison Wesley Longman, Inc., 2000, and Chapter 52 of “Internetworking Technology Overview”, Cisco Systems, Inc., June 1999, which both are incorporated herein by reference.
Another patent assigned to the assignee of the present invention, U.S. Pat. No. 6,182,136 to Ramanathan et al., which is hereby incorporated by reference, is directed to the automatic discovery of service elements. The system uses a discovery template in combination with a discovery engine to drive the discovery routines. The discovery template includes data that triggers selected discovery routines for acquiring information that identifies services and service elements that are anticipated as being cooperative in the execution of core services (e.g., email access, web access, Virtual Private Networks). The system uses the information obtained to create a map of the dependencies of among the actual services (e.g., web access) and actual service elements (e.g., Network File System and Domain Name Service server) within the network.
Although it is known to automatically discover managed devices, prior node discovery systems have aggregated and retrieved information regarding all neighboring nodes. Large and complex networks will have several layers of nodes and many different node types. Thus, a general discovery of all these nodes can delay or prevent the network manager from obtaining information on the desired node types. Therefore, it is desired to provide a network management system that discovers only the desired node types of a network using standard SNMP messages.